I like to analogize this to pixels (although they can be two completely different things)
A pixel is the little dot of color on a screen, the higher the resolution, the more pixels. (resolution is measured in pixels)
Think of this thing as a screen. A long time ago (10 years
) screens were about 1024x768 max. TV's were so thinned out you can see the pixels. However, as graphics card got better, more pixels could be drawn. As technology got better, these higher pixel resolutions also had good framerates.
In this case, think of a 3-dimensional screen. In the video both old and new games use polygons. There is not much detail before because there were less "3d pixels" for the polygon to hook on too. Imagine playing on a 1024x768 (xp average) and an hd screen (1920x1080) more pixels means one can fit more polygons. It just has to have the memory to remember all those "3d pixels" and the technology to draw this larger number of "3d pixels" in faster framerates (for smoother gameplay).
Obviously the two aren't the same and they work differently but I see their evolution pretty similarly.
Mini-blocks are like higher-resolution blocks. One can technically make the blocks so small (super-resolution) to make even blocks look like a realistic elephant
